mPEG-PLGA多孔微球的制备及其对降钙素的吸附行为

以聚乙二醇-聚(乳酸-乙醇酸)共聚物(mPEG-PLGA)为材料,采用溶剂挥发法与快速膜乳化法制备了尺寸均一的mPEG-PLGA多孔微球,用其吸附降钙素,考察了降钙素浓度、吸附时间、离子浓度、温度及pH值及微球性质对吸附的影响. 结果表明,优化的吸附条件为：降钙素浓度1.0 mg/mL, pH 7.4, NaCl浓度0.2 mol/L, 14℃下吸附8 h,该条件下,微球吸附量为48.9 mg/g;吸附量与微球比表面积正相关.     

壳聚糖固载环糊精微球的制备及吸附硝基酚

反相悬浮法制备甲醛保护壳聚糖(CTS)微球,环氧氯丙烷为交联剂β-环糊精反应制得壳聚糖固载环糊精微球。产物用红外光谱、扫描电子显微镜和X射线衍射仪进行表征,并用于吸附2,4-二硝基酚研究。考察了吸附时间、溶液pH值、酚浓度和NaCl含量对吸附的影响。实验结果表明,壳聚糖固载环糊精(CTS-CD)微球具有较好的耐酸碱性能,在pH值为3.6条件下,对2,4-二硝基酚的吸附快速达到平衡,吸附量为325mg/g,吸附符合Freundlich等温方程和二级动力学方程。     

双金属离子交联剂对海藻酸盐凝胶性能的影响

利用Ca~(2+),Ba~(2+),Zn~(2+)与海藻酸钠通过不同配位交联机制形成(Na-Alg)凝胶的特性,两两配伍构建双金属离子交联剂,协同调控Ba-Zn-Alg, Ca-Ba-Alg, Ca-Zn-Alg凝胶微球的结构与性能。采用倒置显微镜、扫描电子显微镜、X射线光电子能谱仪、质构仪等表征微球形貌、结构和力学强度,以牛血清白蛋白(BSA)、罗丹明B(RB)为模式分子评价双金属交联剂对微球负载药物和传质性能的影响。结果表明:Ba~(2+),Zn~(2+)在Alg凝胶中的结合量显著高于Ca~(2+),使Ba-Zn-Alg微球具有致密凝胶结构和较高机械强度;3种微球对BSA的吸附行为属于扩散控制为主的物理吸附,而负载RB微球具有pH值响应释放和扩散传质特征。因此,此研究提供了一种构建微尺度水凝胶药物载体的有效方案。     

羧化改性壳聚糖微球的制备及吸附硝基酚的性能

采用反相悬浮环氧氯丙烷交联、氯乙酸羧甲基化制备交联羧化壳聚糖微球,用红外光谱和扫描电镜对微球进行表征,并用于2,4-二硝基苯酚的吸附研究。考察了吸附时间、溶液pH值、酚的浓度和NaCl等因素对2,4-二硝基苯酚吸附的影响。结果表明,羧化改性交联壳聚糖微球具有较好的耐酸碱性能,对2,4-二硝基苯酚有良好的吸附性能,在pH值为3.6条件下,吸附在瞬间就能达到平衡,吸附量达230 mg.g-1,吸附符合Freundlich等温方程。     

固定化Cu~(2+)螯合亲和膜的制备及其吸附研究

以尼龙66为基膜,环氧氯丙烷为活化剂,壳聚糖为交联剂,亚胺基二乙酸为螯合剂,Cu~(2+)为配位基,制备了固定化Cu~(2+)螯合亲和膜。讨论了该膜对牛血清蛋白(BSA)的吸附机理;研究了BSA溶液初始浓度、pH值和吸附时间对亲和膜吸附量的影响,采用SEM对其表面形貌进行表征。结果表明:较高的BSA初始浓度和pH值,较长的吸附时间均有利于膜对BSA的吸附;Langmuir吸附等温模型和准二级动力学模型可用于该膜对BSA的吸附相关性。     

药物偶联亲和高分子微球对牛血蛋白吸附性能研究

在制备亲和高分子乳液微球基础上,对其进行空间臂改性和药物分子偶联制得PSGN-MTA亲和高分子微球药物。为研究亲和高分子微球生物相容性,考察了高分子微球药物在缓冲液中药物释放行为及对BSA蛋白吸附能力。结果表明,亲和微球表面化学键合MTA药物浓度较高且分布均匀时,对BSA蛋白的吸附过程较符合一级动力学方程。还考察了pH值对BSA蛋白吸附的影响,中性条件时PSGN-MTA微球对于BSA吸附效果较好。     

复合磁性壳聚糖微球对BSA的吸附机理研究

将脱乙酰度为85%的壳聚糖包裹在由二价和三价的铁离子共沉淀制得的Fe3O4磁子表面,用环氧氯丙烷作为交联剂进行交联制成磁性壳聚糖(简称MC),用于吸附蛋白质一磷酸氢二钠一柠檬酸缓冲溶液中的小牛白蛋白(BSA),利用TEM(透射电镜)、IR(红外光谱)、TG-DSC(失重-差热)、XRD(粉末衍射)分析微球的形貌、组成及热件能,考察了牛白蛋白的初始浓度、溶液pH及保温时间对蛋白质吸附程度的影响.结果显示,pH增大使蛋白质的吸附量减小;在一定范围内,增大蛋白质的初始浓度和延长保温时间均有利于增加蛋白质的吸附量,温度对微球吸附蛋白质的影响比较复杂.     

CPVA微球表面接枝对羟基苯磺酸钠及其对茶碱的吸附研究

通过分子设计将2-氯乙基异氰酸酯(CIC)键合至聚乙烯醇微球(CPVA)表面制得CPVA-CIC,再将对羟基苯磺酸钠(HSS)固载于CPVA-CIC上制得功能微球CPVA-HSS。通过红外光谱(FI-TR)、扫描电子显微镜(SEM)及Zeta电位仪对功能微球进行表征,并考察主要因素对接枝微球固载量的影响,探索功能微球CPVA-HSS对茶碱分子的吸附性能及吸附机理。结果表明,通过CIC改性,阴离子单体HSS成功固载于基质CPVA表面,形成功能微球CPVA-HSS。CPVA-HSS对茶碱吸附5 h达到平衡,凭借其强的静电相互作用,pH5时在水溶液中吸附容量可达60 mg/g,随着温度的降低吸附量升高,而随介质盐度的增大吸附容量降低。功能微球的重复使用性较好。     

牛白蛋白包裹复合磁性微球的制备及性能表征

首先在反相(W/O)微乳液体系中制备出Fe3O4/PAM(聚丙烯酰胺)磁性微球;然后在牛白蛋白的磷酸氢二钠-柠檬酸缓冲溶液中,以戊二醛为交联剂,加入Fe3O4/PAM微球,使蛋白质特异性吸附在微球上。采用电子衍射、透射电镜、差热、热重、红外光谱等方法对复合微球的粒径、结构等性质进行了表征与分析。并考察了牛白蛋白的浓度、pH以及保温时间对蛋白质吸附程度的影响。结果显示,微球粒径20 nm左右,粒径均匀;微球具有较大吸附量;pH增大使蛋白质的吸附量减小;在一定范围内,增大蛋白质初始浓度和延长保温时间均有利于增加蛋白质的吸附量。     

淀粉微球的制备及其对污水中Pb2+的去除研究

采用反相乳液交联聚合法制备淀粉基微球,以改性红薯淀粉为原料,N,N-亚甲基双丙烯酰铵(MBAA)为交联剂、Span 60与Tween 60为乳化剂,硝酸铈铵为引发剂得到比较粗糙、近圆球状、比表面积较大的淀粉微球,且在油水相混合前加入。采用红外光谱仪(FT-IR)对其官能团测试、外形图片以及比表面积及孔径分析(BET)等表征方法分析,确立制备条件:改性红薯淀粉2%,引发剂0.109g,转速为180r·min~(-1)。得到的淀粉微球应用于模拟重金属Pb~(2+)溶液中进行吸附初探,改变温度、淀粉微球投入量、pH值探究对吸附的影响,确定最佳吸附条件,应用于西安汉城湖实际水样中进行吸附测试。研究发现,当淀粉微球投入浓度为4.0g·L~(-1)、吸附时间为50min时,pH值为8时吸附效果最佳,Pb~(2+)去除率达到35.4%。     

A study on the adsorption behavior of protein onto functional microspheres

Adsorption has been investigated using bovine serum albumin (BSA) as the model protein and sulfonated microspheres as the matrix. The adsorption appears to be sensitive to time, pH, and ionic strength, and the presence of sulfonate groups can play important roles in this process, increasing the adsorption rate and the amount of protein adsorbed, as well as influencing the interaction of BSA molecules. Fittings from Langmuir's and Freundlich's isotherms indicate that the actual adsorption becomes more complicated than the ideal process, due to the presence of intermolecular interactions of BSA. The determinations under different pH conditions (pH 2.2, 4.3, 7.4) show that near the isoelectric point of BSA (pI 4.7), the amount of protein adsorbed reached a maximum value, and a higher or lower pH resulted in a significant decrease in amount adsorbed. The effect of ionic strength is, however, closely associated with the operating conditions. Copyright © 2005 Society of Chemical Industry     

Investigation of adsorption–desorption dynamism of bovine serum albumin on crosslinked N,N′‐diethylaminoethyl dextran microbeads: Solution phase

New hydrogel microspheres based on crosslinked dextran containing N,N′‐diethylaminoethyl (DEAE) groups with different chemical structures have been used in adsorption–desorption studies. Bovine serum albumin (BSA) is frequently used in biophysical and biochemical studies. BSA has a well‐known primary structure that has been associated with binding of many different categories of small molecules. Both adsorption kinetics and equilibrium isotherms for the adsorption of BSA on crosslinked DEAE dextran have been determined experimentally. These were only slightly dependent on the initial concentration of BSA but were considerably affected by the pH of the medium. The results fitted the Freundlich–Langmuir isotherm model for pH 6.9. The adsorption capacity factor and the adsorption equilibrium constant were obtained and mathematical modeling of adsorption, adsorption rate constants, and maximum adsorption were determined. Swelling kinetics of crosslinked DEAE dextran and optimum ionic strength, pH, and mass of hydrogel were also investigated. Desorption studies were finally determined under optimum medium conditions. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

An in situ study of the deposition of a calcium phosphate mineralized layer on a silicon-substituted hydroxyapatite sensor modulated by bovine serum albumin using QCM-D technology

The deposition of a calcium phosphate (Ca-P) mineralized layer on Si-HA surface (the blank group, Au and the control group, HA) with and without BSA preadsorption was observed in real time using a quartz crystal microbalance with dissipation (QCM-D) technique. The effect of silicon doping on the adsorption of BSA onto a HA sensor was investigated. Approximately 1.5-fold more BSA adsorbed onto HA than Si-HA, indicating the inhibition of BSA adsorption onto the HA sensor by silicon doping. The decreasing ΔD_sat/Δf_sat value in the plots of ΔD–Δf versus adsorption time was predominantly attributed to BSA adsorption, and the decreasing ΔD value with adsorption time during adsorption equilibrium could be explained by the structural rearrangement of BSA on different substrates. Specifically, BSA preadsorption could be a trigger for the formation of nucleation sites for the mineralized layer, promoting nucleation but inhibiting growth. The growth rate was greater on bare substrates than on BSA adsorption substrates. The growth rate of the mineralized layer on the adsorbed BSA layer depended on the substrates in the following manner: Au>Si-HA>HA. The morphology of the mineralized layer depended on the surfaces, and a greater number and a more uniform distribution of smaller nanoparticles were observed on surfaces with preadsorbed BSA. Therefore, BSA could modulate the growth of the mineralized layer at the interface, which is advantageous for fabricating advanced biomaterials.     

Adsorption of BSA on DEAE-Dextran: Equilibria

Abstract

Equilibrium isotherms for adsorption of BSA on DEAE-dextran have been determined experimentally. They were little affected by the initial concentration of BSA but were considerably affected by pH. They were correlated by the Langmuir equation when pH ≥ 5.05 and by the Freundlich equation at pH 4.8 (≈ pI). The maximum amounts of inorganic anion exchanged for BSA were 1 and 0.4% of the exchange capacity of the ion exchanger at pH 6.9 and 4.8, respectively. When NaCl coexisted in the solution, the shape of the isotherm was similar to the Langmuir isotherm but was shifted to the right. When the concentration of NaCl was 200 mol/m³, BSA was not adsorbed on the resin. When BSA was dissolved in pure water, the saturation capacity of BSA on HPO₄ ^2? -form resin was about 3.5 times larger than that with buffer (pH 6.9). The amount of BSA adsorbed on univalent-form resin decreased when the liquid-phase equilibrium concentration of BSA was increased.     

双甘膦修饰磁性四氧化三铁纳米微球吸附DNA的研究

用双甘膦(PMIDA)修饰磁性四氧化三铁纳米微球(MNP)并负载Zn2+制得了PMIDA-Zn2+修饰磁性微球吸附剂。考察了吸附溶液的pH值、离子强度、吸附时间、吸附温度等因素对DNA吸附的影响。结果表明,当吸附剂用量为10mg、pH值为5.0、离子强度(NaCl浓度)为2.0mol.L-1、吸附时间为20min、吸附温度为35℃时,吸附率可达80%,吸附容量为21mg.g-1。被吸附的DNA用3.5%的氨水能完全洗脱。将PMIDA-Zn2+修饰磁性微球用于玉米DNA的提取,所得DNA纯度较高,效果令人满意。     

Equilibrium,Kinetics, and Thermodynamics of Bovine Serum Albumin Adsorption on Single-Walled Carbon Nanotubes

We investigated the equilibrium, kinetics, and thermodynamics of bovine serum albumin (BSA) adsorption on single-walled carbon nanotubes (SWNTs) from aqueous solutions with different pH and temperatures. We analyzed the experimental adsorption equilibrium and kinetic data to evaluate the adsorption characteristics of SWNTs for BSA. The results show that the effects of pH and temperature were important. Moreover, the adsorption isotherm data of BSA on SWNTs are consistent with the Langmuir and Freundlich models, while the kinetics can be expressed by the pseudo-first-order and the intraparticle diffusion rate models. The maximum protein adsorption capacity of SWNTs, which have a surface area of 191.2 m²/g, was found to be 609.8 mg g^?1 at pH 4 and 40°C, and this was the highest value obtained among our previous studies examined with various metal oxides. In addition, the zeta potential measurements were examined to understand the effects of charge density of the surface and the protein on the adsorption process. Thermodynamic analysis results indicate that the nature of adsorption changes with pH. SWNTs were found to be effective for BSA adsorption.     

Synthesis of 5-(4-methacrylamidophenyl)-10,15,20-triphenylporphyrin,its copolymerization with acrylamide and EDMA,use of this copolymer in the adsorption of bovine serum albumin

A rigid and porous polymeric adsorbent was prepared from monomers 5-(4-methacrylamidophenyl)-10,15,20-triphenylporphyrin (1%), acrylamide (39%), and cross-linking agent ethylene glycol dimethacrylate (60%) using suspension polymerization technique. The adsorption behavior of bovine serum albumin (BSA) on this adsorbent was studied as a function of the initial BSA concentration (0.4–2.5 mg/mL), pH (4.0–8.0), ionic strength, and type of salt in buffered solutions under batch equilibrium conditions. The amounts of adsorbed BSA at equilibrium at pH 4.0 and 7.0 for 1.0 mg/mL initial concentration of BSA were 743 mg BSA and 412 mg BSA per gram of the adsorbent, respectively. The adsorption process was nearly irreversible.     

Albumin adsorption from aqueous solutions and human plasma in a packed-bed column with Cibacron Blue F3GA-Zn(II) attached poly(EGDMA-HEMA) microbeads

Affinity dye-ligand Cibacron Blue F3GA, was covalently coupled with poly(EGDMA-HEMA) microbeads via nucleophilic reaction between the chloride of its triazine ring and the hydroxyl groups of the HEMA under alkaline conditions. The microbeads carrying 16.5 μmol Cibacron Blue F3GA per gram polymer was incorporated with Zn(II) ions. Zn(II) loading was 189.6 μmol/g. Cibacron Blue F3GA-Zn(II) attached affinity sorbent was used for albumin adsorption from aqueous solutions and human plasma in a packed-bed column. BSA adsorption capacity of the microbeads decreased with an increase in the recirculation rate. High adsorption rates were observed at the beginning, then equilibrium was gradually achieved in about 60 min. The BSA concentration in the mobile phase also effected adsorption. BSA adsorption was first increased with BSA concentration, then reached a plateau which was about 128 mg BSA/g. The maximum adsorption was observed at pH 5.0 which is the isoelectric pH of BSA. Higher human serum albumin adsorption was observed from human plasma (215 mg HSA/g). High desorption ratios (over 90% of the adsorbed albumin) were achieved by using 1.0 M NaSCN (pH 8.0) in 30 min.     

不同分子质量的腐殖酸对溴离子在MIEX树脂上吸附行为的影响

采用静态吸附法研究了不同分子量的腐殖酸对溴离子(Br?)在MIEX树脂上吸附行为的影响. 结果表明,pH为中性时,4种腐殖酸(分子量分别为小于1000, 1000?5000, 5000?10000, 大于10000)使MIEX树脂对Br?的去除率从80.05%分别降至75.39%, 26.32%, 42.67%和49.03%,而酸性(pH<5.0)或碱性(pH>9.0)时,各种腐殖酸则会促进Br?去除,pH为11.0时去除效率增加最明显. 分子量大于10000的腐殖酸可将吸附平衡时间由60 min缩短至20 min,分子质量1000?5000和5000?10000的腐殖酸可将吸附平衡时间缩短至40 min. 但不论有无腐殖酸,MIEX树脂对Br?的吸附过程均符合拟二级反应动力学模型. 不同分子量的腐殖酸均能明显降低Br?在MIEX树脂上的吸附平衡容量,分子量大于10000的腐殖酸影响最大,但均不改变吸附平衡模型类型,吸附平衡规律用Langmuir与Freundlich模型均可很好描述. 不同分子量的腐殖酸对MIEX树脂去除Br?的影响与溶液pH值密切相关,腐殖酸会加速Br?在树脂上的吸附过程,但不改变吸附平衡及动力学模型类型.